With the trend of tire width toward smaller size, the main stream of a mold in a tire vulcanizer is shifting from a two-piece mold that is vertically divided into two pieces, to a segmental mold.
This segmental mold includes an upper container plate, a lower container plate, and a plurality of divided segments expanding and contracting in radial directions.
An expansion/contraction device for expanding and contracting the segments of the segmental mold is provided to a top plate. These segments are adapted to expand and contract due to an expanding/contracting operation of the expansion/contraction device and the inner structure of the segmental mold.
The mold in a tire vulcanizer needs to be replaced in accordance with the size of a tire to be produced. For this purpose, locking/unlocking means is provided between the expansion/contraction device and the upper container plate of the segmental mold.
As locking/unlocking means provided between the expansion/contraction device and the upper container plate of the segmental mold, for example, locking/unlocking means using a bayonet mechanism as disclosed in Japanese Examined Patent Application Publication No. 5-62046, has hitherto been known.
The locking/unlocking means using this bayonet mechanism includes a bayonet lock provided to the upper container plate and a bayonet claw provided to the expansion/contraction device, and has a configuration in which the bayonet claw is engaged with and disengaged from the bayonet lock.
However, as before, the locking/unlocking means using the bayonet mechanism needs to rotate its bayonet claw provided to the expansion/contraction device to engage with and disengage from the bayonet lock.
Originally, the function of the expansion/contraction device is to expand and contract the segments of the segmental mold by expanding/contracting operations thereof, and hence, the expansion/contraction device has only to have a structure allowing expanding/contracting operations. However, the conventional locking/unlocking means is required to incorporate a rotational mechanism for rotating the bayonet claw into the expansion/contraction device.
In the arrangement incorporating the locking/unlocking means into the expansion/contraction device thereof as described above, a problem has occurred in that the structure thereof becomes complicated correspondingly, as well as the locking/unlocking operation also becomes complicated since the locking/unlocking entails a rotational operation.
The present invention has been made for solving the above-described conventional problem. The object of the present invention is to provide a mold attaching/detaching apparatus in a tire vulcanizer, having locking/unlocking means configured to perform an engagement and disengagement by utilizing a relative movement between the top plate and bottom plate of the tire vulcanizer in a horizontal direction, and thereby capable of being inexpensively constructed by simplifying the structure and operation of the locking/unlocking means.